The Joint Condensed Matter Seminar (JCMS) series is organised by KTH Royal Insitute of Technology, Nordita, and Stockholm University.
On Monday, February 24th, 2025 from 11 am to 12 am we will host a seminar by Paul Leask from Royal Institute of Technology (KTH).
Effect of dipolar interactions on bulk magnetic skyrmions in chiral ferromagnets
I will present a theoretical study of the effect of the long-range dipolar interaction on magnetic skyrmions in the bulk of chiral ferromagnetic materials with the Dzyaloshinksii-Moriya interaction. In addition to the Heisenberg ferromagnetic exchange, I will also allow for the inclusion of anisotropy and Zeeman interactions. Three different Dzyaloshinksii-Moriya interaction terms will be considered. These are related to the Dresselhaus and Rashba spin-orbit couplings and the spin-orbit coupling in Heusler compounds, where each have their own associated skyrmion type (Bloch, Néel and antiskyrmion, respectively). Inclusion of the dipole-dipole interaction breaks the energy degeneracy of these skyrmion types. Furthermore, it is found that the dipolar interaction allows one to evade the Hobart–Derrick theorem without including the anisotropy and Zeeman interactions, by introducing a scale to the skyrmions. For usual chiral magnets without the dipolar interaction, the optimal lattice structure is hexagonal for all three skyrmion types. However, when the dipolar interaction is considered, a salient feature is that this crystal symmetry is broken in Heusler compounds, where the antiskyrmions prefer to arrange in square lattices.